This invention relates to axial mechanical seals and, more particularly, to rotating bellows seals particularly adapted for high speed applications.
A rotating bellows seal is an axial mechanical seal in which a bellows is used to replace a spring to apply an axial force to hold the sealing surfaces together and to provide secondary sealing between rotating members. Bellows seals commonly are formed of two primary elements, namely a bellows adapted to be connected to a rotating shaft and a stationary mating seal ring adapted to be attached to a housing or casing in which the shaft is mounted. The bellows applies the axial force to cause the bellows seal and mating seal ring to sealingly engage one another in order to minimize leakage at the position where the rotary shaft enters the casing.
Conventional bellows seals are relatively expensive and their use generally has been restricted to special environments where other lesser expensive seals are inadequate. Conventional bellows seals utilize a relatively expensive sleeve and mounting means for drivingly and sealingly attaching the bellows core to a shaft. It has also been found that fluids which it is desired to contain within the casing tend to migrate or leak through the sealing interface between the rotary and stationary members and if the fluid migrates into the interior of the bellows core or accumulates at the sealing interface, it can have a detrimental effect on the seal's effectiveness and life span.
Accordingly, it is the objective of this invention to provide an improved rotary bellows seal which is relatively inexpensive to manufacture and install and which has an increased life span in comparison with prior bellows seals.